Reciprocatory engine



Feb. 24, 1953 G. F. MCCLAY 2,629,363

RECIPROCATORY ENGINE} Filed Dec. 22, 1949 INVENT-OR GORDON F. uccuw BYHIS ATTORNEY- Patented Feb. 24, 1953 RECIPROCATORY ENGINE Gordon F.McClay, Lennoxville, Quebec, Canada, assignor to Ingcrsoll-Rand Company,New York, N. Y., a corporation of New Jersey Application December 22,1949, Serial No. 134,440

2 Claims.

This invention relates to engines, and more articularly to a pressurefluid actuated engine of the reciprocatory piston type.

The engine, constructed in accordance with the practice of theinvention, is intended more particularly for use with an apparatus, ordevice, that is required to operate normally at a definitely rated speedand which speed may occasionally require variation. An example of such adevice is that of a spray pipe serving to dislodge matter clinging tothe screens used in the production of paper pulp.

In arrangements of this type, a pipe equipped with spray nozzles iscaused to oscillate across the surface of the screen and the jets ofwater issuing from the nozzles are directed toward the screen to loosenand wash away the clogging matter. Owing to the importance of preventingthe undue dilution of the paper pulp at some of the stages of itsmanufacture, it is essential that the movements of the spray pipe be soregulated as to effect a miximum flushing action with a minimum amountof spray, and it is, therefore, desirable that the stroke of the enginebe variable in order that concentrations of blockin material may bequickly removed and that when the screen has been cleansed the speed ofthe engine may again be quickly and conveniently adjusted for normaloperation.

It is accordingly an object of the invention to enable the speed of theengine to be conveniently and quickly varied in accordance withimmediate requirements.

Other objects will be in part obvious and in part pointed outhereinafter.

In the drawings accompanying this specification and in which similarreference numerals refer to similar parts,

Figures 1 and 2 are longitudinal views, partly broken away, showing themovable parts of the engine in opposite hand limiting positions.

Referring more particularly to the drawings, the engine designated 20,in its entirety, comprises a cylinder 2| which is recessed to form apiston chamber 22 consisting of a large bore 23 and a reduced bore 24that opens at one end into the large bore 23. At the opposite ends ofthe cylinder 2| are external flanges 25 and 26 that respectively abut ahead 21 and a support 28 and are secured to these parts by bolts 29.

A closure is provided for the outer end of the 2 to be actuated. Thehead 30 is recessed to receive a packing member 35 that encircles therod 33 to prevent leakage of fluid from the piston chamber and saidpacking member is retained in position by a plate 36 overlying the outerend of the head 30 and held in assembled position by the bolts 3 I.

The rod 33 is separable from the piston 34 and has, to this end, a stem31 threaded into the small portion or stem 38 of the piston lying withinthe bore 24. At the juncture of the stem 3'! and the body of the rod 33is a shoulder 39 that bears against the portion, or head, 40 of thepiston lying within the large bore 23 for pressing said head against theend of the portion 38.

The outer end of the head 40 constitutes a pressure surface 4| that isintermittently subjected to pressure fluid for actuating the piston inthe direction of the head 21 and the free end of the stem 38 of thepiston serves as a pressure surface 42 that is constantly subjected topressure fluid conveyed thereto by a passage 43 leadin from an endportion 44 of a valve chamber 45 which is in constant communication, atsaid end portion, with a source of pressure fluid supply (not shown)through a conduit 45.

The valve chamber 45 extends transversely of the head 21. Itsintermediate portion 41 is of reduced diameter and opens at one end intothe end portion 44 and at its opposite end into a similar end portion48. The ends of the portion 41 of the valve chamber contain bushings 49and 50 having beveled seats 5! and 52, respectively, for ball valves 53and 54, and between the valves 53 and 54 is a spacer in the form of arod 55 which is movable endwise in the bushings 49 and 50 and of alength to prevent the valves from engaging their seats simultaneously.

The ball valve 53 is normally held on the seating surface 5! by thepressure fluid in the end portion 44 acting against an actuating surface56 of said valve. Such pressure is augmented by a spring 51 that seatsat one end against the valve 53 and at its other end against a closure58 for the adjacent end of the valve chamber.

The force serving to lift the valve 53 off of its seat and press thevalve 54 against the seating surface 52 is imparted thereto by a plunger59 slidable in the portion 48 of the valve chamber and seating at oneend against the valve 54. The opposite end of the plunger 59 rests upona diaphragm 60 which is clamped, at its marginal portion, to the head 21by a cover 6! and bolts 62, and in the cover is a chamber 53 into whichpressure fluid is intermittently conveyed by a passage 64 in the head 2!and the cylinder 2|.

The passage 64 opens into the small bore 24 at a point near its juncturewith the large bore 23 so that the piston will uncover it immediatelyprior to the end of its stroke. The passage 64 also conveys exhaustfluid from the chamber 63 and the small portion 38 of the piston isaccordingly provided with an annular groove 65 adjacent the head 40 toregister with the passage 64 in the opposite hand limiting position ofthe piston for conveying such fluid to a vent 66 at the inner end of thelarge bore 23.

In the form of the invention shown, the combined lengths of the bushings49 and 58 is less than the length of the intermediate portion 41 of thevalve chamber so that a space 5'! exists therebetween and leading fromsaid space is a passage 68 that extends through the head 21 and thecylinder 2| and opens into the outermost end of the large bore 23. Thepassage 63 serves both as a supply passage and an exhaust passage and.is provided with means for varying the rate of admission. to and thedischarge of fluid from the bore 23. To this end a needle valve 55 isthreaded into the cylinder to extend with its valve portion l into thepassage 58 at the juncture of the latter with the bore 23. The fluidexhausted from the bore 23 returns to the space and passes through thebushing 53 into the end 58 of the valve chamber whence it passes to theatmosphere through an exhaust port H.

In the operation of the device, and assuming the movable parts of theengine to be in the positions shown in Figure 1, the pressure fluidentering the small bore 2& of the piston chamber will act against thepressure surface 42 to drive the piston in a right hand direction, asFigure l is viewed in the drawings. The chamber 63 Wfll then be open tothe atmosphere through the passage 64, the annular groove 55 and thevent 69 so that the spring 5i and the pressure of the fluid against theactuating surface 56 will hold the valve 53 against the seating surface5i to prevent the flow of pressure fluid into the space 61. In theclosed position of the valve 53 the rod 55 will hold the valve 5unseated to afford communication between the space 6? and the port l lThus, as the piston moves rightwardly the air in advance of the head 20will be expelled from the bore 23 through the passage 68 into the spaceEl, thence through the bushing 50, the end portion 48 and the port H tothe atmosphere.

As the piston approaches the end of its stroke, in the directiondescribed, the free end of the small portion 33 uncovers the passage G4.Pressure fluid will then flow from the small bore 24 through saidpassage into the chamber 63 and, acting against the plunger 59 throughthe diaphragm Gil, will move the valve 54 against the seating surface 52to cut-off communication between the passage 88 and the port l i. Thismovement of the valve 5Q, transmitted through the rod 55, will lift thevalve 53 oil of its seat. Pressure fluid will then flow from the end '34of the valve chamber through the bushing 49, the space 61 and thepassage 68 into the outer end of the large bore 23 and drive the pistonleftwardly, thereby completing the cycle of operation. During thismovemnt of the piston pressure fluid will be expelled from the bore 24through the constant supply passage 43 and the pressure fluid in thechamber 63 will be retained therein until the annular groove 65registers With the passage 64. The fluid in the chamber 63 will thenescape through the passage 66, the annular groove 65 and the vent 66 tothe atmosphere to permit the return of the valve to its seat and theunseating of the valve 54 preparatory to a new cycle of operation.

Whenever, during the operation of the engine, it is desired toaccelerate or decelerate the movement of the piston 34, the needle valve69 may 4 be adjusted to either increase or decrease the flow area aroundthe valve portion H! of the needle valve 69.

I claim:

1. A reciprocatory engine, comprising a casing having a differentialbore, a reciprocatory piston in the bore having portions correspondingto the diameters of the bore, a passage in the casing to constantlyadmit pressure fluid into the small end of the bore, a second passage inthe casing for conveying pressure fluid to and exhaust fluid from theopposite end of the bore, a valve chamber in the casing having anatmospheric vent, valve means in the valve chamber for controlling theflow of fluid to and from said second passage, a kicker passage in thecasing controlled by the piston for valving pressure fluid to the valvemeans for throwing the valve means to a position for admitting pressurefluid into said second passage, an actuating surface on the valve meanssubjected constantly to pressure fluid tending to move the valve to aposition for cuttingoif the admission of pressure fluid to said secondpassage and to establish communication between said second passage andthe atmospheric vent, a spring acting against the valve means to augmentthe pressure of the fluid acting against the actuating surface, andmeans for selectively controlling the rate of flow of fluid through saidsecond passage.

2. A reciprocatory engine, comprising a casing having a differentialbore and an exhaust port for the bore, a reciprocatory piston in thebore having portions corresponding to the diameters of the bore, apassage in the casing to constantly admit pressure fluid into the smallportion of the bore, a valve chamber in the casing having a vent, asecond passage in the casing for conveying pressure fluid from the valvechamber to the large portion of the bore and to convey exhaust fluidfrom said large portion to the valve chamber, reciprocatory valve meansin the valve chamber, fluid actuated means for throwing the valve to aposition for admitting pressure fluid into said second passage, 2.kicker passage in the easing for conveying pressure fluid from the smallportion of the bore to the fluid actuated means and being controlled bythe piston, a groove in the piston for communicating the kicker passagewith the exhaust port to permit the exhaust of the fluid acting againstthe pressure surface, an actuating surface on the valve means subjectedconstantly to pressure fluid tending to move the valve means to aposition for cutting-01f the admission of pressure fluid to said secondpassage and to establish communication between said second passage andthe vent, a spring to augment the pressure of the fluid against theactuating surface, and means for selectively controlling the rate offlow of fluid through said second passage.

GORDON F. MCCLAY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number

